Harry Potter and the Irken Invader
by InvaderChic159
Summary: Zim gets sent to Hogwarts, hoping to learn spells to conquer Earth. He's about to get a little more than he expected...
1. I used the humans to my advantage

**First note: I have an update policy. I'll only update if I get two or more new reviews for each new chapter. That way, I can be sure that people are actually reading it. I ACCEPT ANONYMOUS REVIEWS.  
Second note: This is the disclaimer. I do not own Harry Potter or Invader Zim, nor do I own any of their respective characters. Thank you.**

Zim had just ended a transmission to the Tallests when GIR crashed into him. "GIR!" He yelled angrily, and the defective SIR unit got off him.

GIR got off the alien and said, "There's a birdy at the window!"

"What…? Why are you telling me this, exactly?" Zim asked, annoyed. But, nonetheless, he took the elevator back up to the house level. When he got out, he saw that GIR was right. There was a large bird tapping at one of the windows. The first thing Zim thought was that GIR had actually remembered to keep the windows closed. That in itself amazed him.

He walked over to the window and looked at the bird. If he remembered correctly, this bird was an owl. But owls only came out at night, at least to Zim's understanding. So what was it doing here, in broad daylight? After a second look at the bird, he realized that an envelope was tied to its leg. This puzzled him, and his curiosity got the better of him, so he opened the window, letting the bird in.

It landed on the windowsill and held out the leg with the letter attached. Zim untied it, and the owl flew away. How strange… He closed the window and looked at the envelope. It felt heavier than normal paper, and looked a bit older, almost yellow. His name was written on the back in very neat script. Who would send a letter to him? And by owl, no less?

He tore open the envelope and pulled out the paper inside. It was very similar to the envelope, in that it was a heavier and older paper. The same fine script filled the page.

After reading the letter, which said it was 'Hogwarts School for Witchcraft and Wizardry', he was puzzled. He couldn't tell if this was a prank, or if it was real. After all, he'd seen magic on TV, but it had always been fake. There was no truth to it. Yet this letter seemed so official, and seriously, who would find an owl and make it fly to his house in the middle of the day just for a prank?

"GIR!" He yelled to the robot, who raced to his side. "We're going to London!"

The only problem was: he didn't know where London was. But, luckily, that's what his computer was for. After getting the location of the city, which was somewhere called 'England', across the ocean, Zim decided that the fastest and easiest way there would by the Voot Cruiser. The only real problem was that it was tiny, and if the letter _was_ real, then he'd need to bring a lot of his stuff, because he'd be staying at that school for eight months.

Luckily, the Invader didn't have a change of clothes, so that wouldn't waste space. He brought his portable communicator, to still be able to report to the Tallests, all of his repair tools, just in case something happened to his PAK, and some other trinkets. GIR sat in the cockpit with him, with duct tape over his mouth so that he couldn't start singing the Doom Song on the way.

They reached England, and landed in a forest near their destination. He frowned. "I hate cities," he said, remembering the time that he'd been stupid enough to get lost in the city _on purpose_, making the mistake of trusting GIR to get them home. But he turned on the newly installed cloaking device for the Voot Cruiser and quickly donned his disguise. It wouldn't do to go into a human city without it.

Of course, with his skin still green, he got quite a few weird looks anyway. GIR, donning his dog suit, didn't help much. "Where am I supposed to go?" Zim growled under his breath, angry that the letter and list hadn't included _where_ he'd get all of his supplies. All he had to go on was the return address that said London, and here he was, with no idea where to go from here.

Zim saw a very large man leading a boy into a building, and could just barely hear him saying something about 'Hogwarts school supplies', so he quickly followed so as not to lose them. Though, it'd be hard anyway, since the man was about twice the size of everyone else. The place went silent as soon as the black haired boy walked in, so Zim started to wonder if he was someone important. Neither he nor the man noticed him until they had gone out the back door.

"Who're—why is your skin green?" the boy asked, staring at him.

"It's a skin condition," he muttered. The boy didn't even _want_ to ask about GIR, since the robot was currently chasing a random butterfly. He really didn't want to know.

Zim followed them through the doorway, but as soon as he was through, he darted away. He didn't need humans helping him in any way. They just happened to have been going the same way, and only the large man knew the way in. He didn't want them thinking otherwise.

He wandered for a while before realizing something very stupid. He didn't have anything to pay with. All he had on him was Irken moneys, and he knew they wouldn't do any good here on Earth. Great, now what was he supposed to do? He ran through options in his head.

Option 1: Steal what he needed. It wouldn't cost him a thing, and he could get everything that he needed. The only problem was, if he got caught, he was screwed.

Option 2: Find that boy again and try to con him to get money. Or pickpocket him. Whichever worked better. The problem with that was that that would require Zim asking a human for help.

Option 3: Just go home and forget the whole thing.

As tempted as he was to go with Option 3, his curiosity nagged him, begging to be told what this was all about. So, no matter what, he _had_ to make it to Hogwarts, even just to satisfy that annoying part of his brain. And who knew? If they really _did_ teach magic, maybe he could learn magic powerful enough to aid with his plans to conquer the Earth. The possibilities would be endless!

One sacrifice was okay for a bigger goal, he reasoned. So with that, he went to find the boy and the giant of a man.

Zim got lost many times, and half the time, he was chasing after GIR, who'd seen something shiny. After nearly an hour of searching, though, he finally found them. They had stopped for a bite to eat. He walked up to them and swallowed his pride for a moment. "Um, I have a little bit of a problem," he told them, using his best 'poor, lost kind' voice. "I have to get stuff for my first year, but I don't have any money…"

The other boy frowned. "Well, if you really need money, I can lend you some of mine, and just pay me back when you've got enough," he said, pulling out a heavy looking pouch of coins. Bingo!

Zim grabbed the pouch, and resisted the urge to just run away with it. He went to all the shops and retrieved his supplies. He was weighed down by all the stuff, even though GIR was carrying a lot of it, when he arrived at the last place he needed. He'd found someone random on the street to point him towards Olivander's, the only place in London where he could get a wand.

When he walked in, the bell on the door rang a bit, and after a moment, an old man came into view, walking to the desk. "Hello," he said, looking at Zim quizzically. "What can I do for you?"

"I need a wand," Zim said. "I'm starting school at Hogwarts this year." He was feeling really uncomfortable under the old man's stare.

"I see…" the man said, and went to the back to try and find a wand for the alien. After about six tries, Zim finally found his wand: sycamore with dragon heartstring. The old man looked at him again. "Maybe we'll see each other again, someday, alien boy."

Zim froze on his way out. No. there was no way this old man could see through his ingenious disguise! "I-I don't know what you're talking about…" he said, and quickly walked out, still feeling the old man's stare bearing through the back of his head.

At the end of his shopping, Zim had ended up spending literally all of the money the boy had lent him. There was absolutely nothing left in the pouch.

When Zim and GIR finally made it back to the Voot Cruiser, Zim realized a serious problem: How was all of this going to fit into the Voot Cruiser, with him still being able to fly it? He began trying to pack everything in, and finally, after what seemed like hours of work, everything managed to fit comfortably.

Now, yet another question arose: where was he supposed to stay until he had to get on the train to school? He banged his head on the windshield of the Voot Cruiser, grumbling.

He managed to live in his vehicle for the last few weeks until he had to go. He and GIR made sure everything was packed enough to be able to carry and headed back to the city to find the train station.

They were forced to stop and ask for directions, but they arrived at the station with time to spare. It was a good thing, too, because he had no idea how to reach 'Platform 9 ¾'. He looked around hopelessly until he saw a family going towards the wall between platforms 9 and 10. The boy from London was with them. They ran straight through the wall, and Zim watched, a bit surprised. He quickly got over it, though, and tried to do the same. He expected to just hit the wall, so one of the legs from his PAK reflexively popped out to brace against the wall to stop his from breaking something, but instead, he plowed right through. The leg quickly retreated, unnoticed.

Zim's eyes fell on the huge train in front of him, astounded at its sheer size. Yes, the Massive was much, much larger, but for a human land transportation unit, it was _huge_! He and GIR dragged his bags on the train and picked an empty seat in the back. He stared out the window while GIR started singing the Doom Song for no apparent reason. Luckily, Zim had zoned out too much to listen, or he would have strangled the poor robot.

His mind was wandering to the year ahead. What kind of stuff could he learn? Would he be able to use it to silence Dib once and for all, and conquer the Earth for the Irken Empire?


	2. GIR's going to be a handful

**Okay, like I said before, I don't own either series, I just own the plot. 'Kay?**

Zim snapped out of his thoughts when he heard footsteps coming his way. He quickly shoved GIR up on the luggage rack, closing it and sitting back down like there was nothing wrong. The door to his seat opened, and the black haired boy leaned in, with a red-headed kid behind him. Zim vaguely recognized him as one of the kids the other boy had followed through the wall.

That black haired boy seemed to pop up everywhere Zim looked, and frankly, it was starting to annoy him.

"Yes?" he asked. "Do you need something?"

"Uh, well, we were wondering if this seat was taken. All the others are already full," the boy said.

Zim sighed. To just turn them away would be suspicious, wouldn't it? So he scooted over closer to the window and sighed. "Yeah, yeah, whatever."

Both human boys got into a conversation that Zim was only half paying attention to. He learned that the red-head's name was Ron Weasley, and the other's was Harry Potter.

Ron had gasped at learning that, and if Zim hadn't been wearing his disguise, his antennae would have perked up. His wig, however, got in the way. For the first time since Ron and Harry sat down, Zim decided to speak.

"Why is this so important?" he asked, trying to satisfy that damned curiosity of his. He turned to Harry. "Why are you famous?"

"Um, well," Harry started. "I guess, a long time ago there was an evil wizard named Voldemort, who killed thousands of people, I think. He killed my parents, but for some reason, when he tried to kill me, it backfired."

"He's known as the Boy Who Lived," Ron piped up. Zim didn't care much about that, though. His thoughts were stuck on Voldemort. This magic _could_ be useful for him. A mere human was able to use it to kill thousands. Naturally, Zim, with his superior Irken intellect, could kill millions, maybe even billions, making the earth that much easier to take over for the Empire! He'd start with that annoying Dib-human…

"Hey," Ron said, and Zim had a good idea as to what the human was going to ask. "Why is your skin green?"

Zim gritted his teeth. He was bound to get a lot more of this. People here in 'England' seemed to be a lot smarter than those at his old skool. They may even be close to his level. "It's a skin condition," he growled out, and Ron scooted away from the ticked off alien.

"Oh, yeah," Harry said. "I forgot to ask before. What's your name?"

"I am Zim," he said, trying to desperately hold back yelling his name as he usually did. These humans, he realized, would probably find that a bit strange, and he had to produce an aura of 'normal'. He went back to staring out the window, while the boys bought candy from the trolley.

"Want some?" Ron asked, holding out a handful of bean-type candies to Zim. The alien shook his head frantically, knowing what most food seemed to do to him. He didn't trust these candies, and refused to have any.

The door opened again a little while later, and a girl with bushy brown hair and abnormally large front teeth poked her head in. "Have you seen a toad anywhere around here?" she asked. "A boy named Neville's lost one."

As soon as she finished the sentence, they heard a croaking sound coming from the luggage rack. Zim smacked his forehead. "GIR!" he yelled, and the robot in disguise fell from it. He was squeezing a toad. "GIR, let the toad go."

"But it likes me…" GIR said.

"GIR!" Zim yelled.

"Aww…" GIR said, letting go of the toad. Three heads honed in on the green colored dog.

"Did your dog just talk?" the girl asked. "How…?"

They kept trying to get Zim to tell them how it was that GIR was able to talk, but after he gave them a full five minutes of silence, they gave up.

"Wait a minute," the girl said, studying Zim. "Why…?"

"He's got a skin condition," Harry jumped in. She didn't look convinced, but left that for later. "By the way," she said, finally picking up Neville's toad. "I'm Hermione Granger. And you are?"

"I'm Ron Weasley," the redhead said.

"Harry Potter," the Boy Who Lived told her, and she stared. "Oh my god…" she whispered, apparently stunned to actually be talking to a famous person. She seemed to get over it after a moment, and looked at Zim expectantly. He realized she was waiting for him to introduce himself.

"That's Zim," Ron said through a mouthful of some sort of pastry.

"I see," she said. "Well, you'd better get changed, we'll be arriving soon." And with that, she left, probably to return the toad.

Zim narrowed his eyes at GIR. "Do I have to specifically _tell_ you not to steal other people's pets?"

GIR lowered his head, and gave an honest answer. "Yes."

Zim sighed, rubbing his temples. "Don't steal other people's pets."

"Okay!" GIR said, saluting his master. All the while, the two other boys watched with confused expressions.

Zim shooed them out while he was changing, using the excuse that 'he was shy'. Irken had no external reproductive organs. They would certainly notice that, and he had no excuse to explain that away.

They arrived at the school, and Zim's eyes widened. Again, the Massive was still much larger than this, but for a human structure… it was amazing!

"Firs' years!" a voice yelled, and he looked up to see the large man from before holding a lantern. "Firs' years over here!"

All the first years made their way over to him, and Zim gulped. This was bad. They had to get into boats. Open topped, flimsy boats, that looked like they could easily be tipped over.

He got in a boat with Harry, Ron, and a boy holding the toad from before. Zim assumed the boy was Neville. He'd made GIR fit into the suitcase he'd gotten, so he'd be taken up with the luggage. He looked over the side, eyes wide with fright. This could go wrong so easily.

"What the matter?" Ron asked. "Do you get seasick?"

"Huh? Uh, oh, yes. Oh how seasick I get!" Zim said, never taking his eyes off the deadly liquid.

He tried to take his mind off the water by thinking about what he'd heard about the four 'Houses' in Hogwarts: Gryffindor, Hufflepuff, Ravenclaw, and Slytherin. Many people had spoken about how awful Slytherins were, how nearly every wizard ever put in Slytherin turned evil. Zim smirked at the thought. It was just the House for an Invader like himself.

When they reached the castle, Zim was the first out of the boat, and they headed up to the castle. He boredly listened to the explanation of the Houses, and walked with the other First Years into the Great Hall. That one room was bigger than his entire base! It was incredible! He shook his head. No, he couldn't become impressed with these things humans had created. Irken technology and structures were much better.

The names were called, and Zim, naturally, was last on the list. He had no last name, which seemed to confuse everyone. He'd have to fix that later.

The Hat was placed on his head, and was silent for a long time. "Where are your thoughts, boy?" it asked, actually sounding confused.

"Eh?" Zim asked, confused, but then realized. That was how the Hat sorted you. It checked your personality and placed you where you fit best. It probed the brain for thoughts, and that was exactly the problem. All of Zim's thoughts were stored in his PAK. His brain had minimal use.

The Hat finally managed to get a glimpse of the last few hours in Zim's mind, and noticed him conversing with Harry Potter and Ron Weasley, both of whom it had placed in Gryffindor. So there was only one thing to do.

"GRYFFINDOR!" It roared, and Zim opened his eyes in confusion. Why would the Hat put him in a House with goody-goodies? But, nonetheless, he hopped down from the stool and walked over to the table of scarlet and gold. He was in a bitter mood throughout dinner, and didn't touch a single food on the table.

He vaguely heard the old man at the front of the Hall, who he assumed was the Headmaster, Professor Dumbledore, tell them something about the Forest and third floor corridor being off limits. Of course, to someone like Zim, who did whatever he wanted, these meant nothing.

He went with the group of students up to the Gryffindor Common Room, and actually decided to listen for the password. That would actually come in handy. The older redheaded boy had said, "Caput Draconis."

Zim knew they were being told about the way the dorms were set up, so he zoned out again. He was angry as to the House he'd been Sorted into. How _dare_ the Hat put him here! When they were 'released' to go to bed, Zim stalked up the stairs to the boy's dormitory and stopped in the doorway. "GIR!" he yelled.

The room was already a mess. Clothes were strewn everywhere, and ink was spilled on the floor. One of the beds had somehow been overturned.

"What happened here?" One of the other boys, Seamus Finnegan asked, wondering what could cause such a mess.

"I did!" GIR said, popping up from under a mound of clothes. Zim pounded his head against a wall. At least GIR hadn't actually thrown things out of _his_ suitcase. It would have been bad for them to find his Irken technology he'd brought with him. Very bad.

The other boys quickly got ready for bed and crashed. Zim, on the other hand, sat on the overturned bed, bored. They'd made him take that bed since it was _his_ 'dog's' fault that the mess was there in the first place. As an Irken, he required only a minimum of two hours of sleep. It was going to be a long night if he did nothing. So he crawled over to his own suitcase and pulled out one of his textbooks. He had nothing better to do, so he might as well prepare himself for the days ahead.

He removed his itchy lenses and blinked a few times, glad to have them off. He'd have to leave his wig on, though, just in case any of the other boys awoke in the middle of the night and saw him. An arm-like thing came out of his PAK and there was a light at the end, to serve as his reading light for the night.

After hours of skimming through A History of Magic, Magical Theory, and Fantastic Beasts and Where to Find Them, his eyelids slowly started to droop, so he set his books down, and the light retreated into his PAK. Even though the underside of a bed is pretty uncomfortable, he managed to fall asleep very quickly.

**Sorry to those of you who wanted Zim to join Slytherin. But I've got most of this story completely mapped out, and for it to work requires Zim to be put in Gryffindor. And besides, the Hat **_**does**_** probe the brain, and Zim's thoughts and memories are usually kept within his PAK. The Hat just picked up vague traces of the last few hours, so, since it had no view on Zim's personality, it just put him in Gryffindor based on his recent 'interactions'. Believe me, Zim's **_**not**_** happy.**


	3. She's Becoming a Problem

**Disclaimer: I hope you get it by now. The website title **_**fan**_**fiction should really say it all.**

Zim was also the first to wake the next morning, which worked to his benefit. He was able to put his lenses back in without anyone questioning it. Plus, he had to fix his wig, which had fallen a little.

He went down to the Common Room, sitting by the fire until everyone else slowly made their way down.

"What time did _you_ get up?" Harry asked, yawning. He was still most of the way asleep, as opposed to Zim, who was awake and already dressed.

"About four thirty," Zim responded. "Why?"

Everyone in the Common Room stared at him. How could he have gotten up so early and _not_ be exhausted?

They made their way down to the Great Hall for breakfast, and Zim's squeedly spooch growled. Great, he was hungry, and he wasn't even very sure what was safe for him to eat and what wasn't.

When they sat down and the food appeared, Zim scanned the table for something small. Maybe an apple? Could he eat that? He picked one up and sniffed it. It seemed to be okay. He took a hesitant bite, oblivious to the stares he was getting, and sighed with relief. Okay, apples were safe. That was good to know.

They went to their classes, and Zim was asked many times about his skin. He just stopped answering, so all the other kids had to ask people who _did_ know. Near the end of the day, between their last class and dinner, Zim was sitting in the Common Room, actually feeling quite weak. His mind felt a little clouded. He tried to stand up, and a lot of the color drained from his face. Luckily, Neville had been in the Common Room with him, and rushed him out to the corridors. Unfortunately for both of them, neither knew where the Hospital Wing was.

They got lost multiple times, until Zim finally passed out.

When he awoke, he was laying in a white bed. A teacher had found him and Neville, and rushed him to the Hospital Wing immediately. He noticed two things. One: Professor Dumbledore was the only other person in the room, and two: he wasn't wearing his wig. He reached out towards the table where it lay, even though he knew it was a lost cause. Dumbledore had clearly already seen him with it off.

"You don't need to worry," the Headmaster said. "I already knew. You're from the Irken Empire."

Zim stared at him, dumbfounded. How the _hell_ did he know that? "How—"

"I have my sources," Dumbledore replied with a bit of a smile. He grew serious. "Am I correct in assuming that your PAK is what sustains your life?" Zim knew he had to answer truthfully, so he nodded. "That would be the problem, then," Dumbledore said solemnly. "There's a spell on the school grounds that prevents technology from working."

Zim stared at him. "But GIR's working just fine. He trashed the dorm last night…"

"I think, because he and your PAK are a different technology, it works more slowly, because it has to adapt to the new technology. So, eventually your robot will shut down."

"Does that mean I'm going to die?" Zim asked with wide eyes. He couldn't die, not like this. This would be a pathetic death. He'd rather die in battle.

Dumbledore shook his head. "Alterations to the spell are being made as we speak. You'll be fine, I promise. However, try to use the 'extra additions' very little for the next few months. It may wear you out."

Zim nodded, not even bothering to ask how he knew about the legs, light, communicator, etc., knowing that he'd get no proper answer. "How long have I been in here?"

"Oh, a few days," Dumbledore responded. "It's Friday morning."

"Am I good to go now?" he asked. He remembered on the schedule what was first thing Friday morning: Potions. It was something he was looking forward to. He'd already had many experiences mixing chemicals and such together, and found it very fun.

Dumbledore chuckled a little. "I suppose so. You run along, and I'll let Madame Pomfrey know." And with that, Dumbledore left and Zim jumped up, put his wig on, and sped off down many sets of stairs. He figured that as long as he just kept going down, he'd have to reach the dungeons at some point.

Just as the door was closing, Zim slipped through into the Potions room and smiled. He was going to enjoy this.

While he'd been living in the Voot Cruiser, Zim had read through his Potions textbook, intrigued by the many things that could be done with just a few simple ingredients. It fascinated him. The teacher, Professor Snape, was hounding on Harry, answering questions that the boy couldn't answer. Zim nearly laughed at his idiocy. Clearly, the boy hadn't touched a single textbook since he'd bought them. Pathetic.

As the class droned on, Zim realized that this 'Professor Snape' seemed a lot like Ms. Bitters, in that he seemed to hate the students with a burning passion. Why people like that became teachers was beyond Zim.

When they were finally given directions to make a potion, Zim's mood instantly brightened. The potion was extremely easy, so Zim made it with ease. He could have done it with one hand behind his back. He laughed to himself as Neville managed to burn a hole through the bottom of his cauldron.

When Snape neared Zim's cauldron, he made a disdainful face, even though Zim knew he'd brewed it to perfection. He glared daggers at the teacher, and bottled it to hand in. Snape would see just how well Zim had made it himself. Then he'd see…

Since Zim had finished extremely early, he spent the rest of the class watching the other idiots around him. It was pretty funny. When they were finally released, Harry walked over to him. "That was pretty hard," he said. "I feel bad for Neville."

"Why?" Zim asked. "I thought it was funny. And that potion wasn't hard." He laughed.

The girl, Hermione, walked up beside them. "He's right. It was pretty simple, really."

Harry frowned, feeling very stupid between the two of them. He dropped back, and Hermione pulled Zim to the side.

"I want an explanation," she hissed.

"Of what?" Zim asked coolly. Yes, this human was smart, but he'd surely be able to outsmart her.

"There's no skin condition that turns your skin green," she told him. "So fess up."

"It's a rare disease," Zim answered, trying to hide his nervousness. This girl was becoming a pain in the rear. Something would have to be done about her…

They were pushed along, forcing Hermione to let the alien go. "Don't think I'm letting this go," she warned before stalking off. She reminded him a bit of Dib, only less… crazy. Dib was paranoid. And stupid. This girl actually used her brain. She could become a real danger if something wasn't done soon.

At lunch, he overheard a conversation between Ron, Harry, and two of Ron's older brothers, twins named Fred and George.

"Who's the green kid over there?" One of the twins asked.

"Oh, that's Zim. He's got some sort of skin condition, and he's pretty sensitive about it," Ron replied.

"Maybe I should ask him to tutor me in Potions…" Harry told them. "I don't get it at all."

"Why would you ask him?" the other twin asked. "I wouldn't have pegged him for the smart type."

"He said that that potion we made today was _easy_, though," Harry said. "I think he finished really early."

"Maybe I should ask him to tutor me too," Ron said.

"Then go ask him," Harry said, nudging him.

"It was your idea, you go ask him," Ron said in response, and the twins started laughing. Zim was laughing to himself a little, too. Both were afraid to ask him for help. Good. He'd have said no anyway. He wasn't going to waste his precious time helping humans with their homework.

"Wasn't he in the Hospital Wing for a few days?" Ron asked, and Harry nodded.

"Yeah, Neville said he looked really pale and passed out. No one knows what he had, though."

"Well, he looks much better," Ron said, and looked up to see Zim glaring daggers at the two boys. "Well enough to be angry, at least," he said, turning away. Zim laughed again. It was nice to inflict fear in his classmates. That was something he hadn't been able to do before. His old classmates had been too stupid to realize when they were in danger.

He stretched and stood up, leaving so that he'd be early for the next class: Defense Against the Dark Arts. He heard it involved a lot of stairs, and if he was lucky enough, no one else would be in the corridors, and he could use his PAK to help him get up them.

He was in luck after all. The spider legs came out and lifted him off the ground. They scuttled, and he raced up the stairs, oblivious to the gossiping paintings now staring at him. When he reached the door, the legs retracted, and he sat down on the floor, feeling very worn out, which he didn't understand at first. Then he remembered Dumbledore's warning about using his PAK. At least he had some spare time to catch his breath before class.

When it was finally time to enter, he stumbled into the classroom. This class was going to bore him, he just knew it. He'd much rather be learning about the Dark Arts themselves than how to protect against them. It didn't help that the teacher was a frightened, stuttering fool-human.

The day went on, leaving Zim in a constant state of boredom. He didn't touch anything at dinner, and was the first one up to the Common Room. He didn't want anyone to try and start a stupid, pointless conversation with him. He headed up to the dorm, to see what kind of a mess it was now, and smacked his forehead. It was even worse than before. That stupid robot would never learn.

He laid on his bed, which was upside down again, and sighed. He laid like that for a few moments before sitting up and taking out some of his homework. This was quite difficult, however, because he had a very annoying SIR unit poking him every five seconds.

"GIR!" he yelled. "Quit it, I'm trying to do homework! Go downstairs and bother someone else or something…" To his surprise, GIR listened, and a few moments later, he could hear angry yells from the Common Room. Oh well, as long at GIR wasn't bothering _him_.


	4. Alarm Clock

**Don't own IZ or HP. Get it? Got it? GOOD.**

As the other boys came up to bed, Zim put his homework away. He'd manage to finish all of it, so he had some time to himself. But what to do now? He had no interest in reading his textbooks right now, and had nothing else to do. As soon as he was sure everyone else was asleep, he crept down to the Common Room, intending to leave and explore.

He managed to quietly open the portrait doorway just enough to slip through without waking the Fat Lady, and crept down one of the staircases. Most of the paintings were asleep, and those that weren't were soon on their way, so none of them noticed the alien.

He had a few close calls with teachers. They would be coming around the corner, and he had nowhere to run. Luckily, he remembered his PAK and just went up. The legs were capable of moving on ground, walls, and ceilings, so he was able to stay out of trouble.

Zim reached the seventh floor, where there seemed to be nothing interesting. There were no teachers here, so he was safe to pace freely. He needed a base here. Because of the spell over technology, there was no guarantee that the portable communicator would work. He wouldn't be able to contact the Tallests!

Just as he thought that, a door slowly appeared on the wall, and he walked forward to inspect it. He nudged it open and gasped. There, in the room, was a base exactly like the one he'd set up when he first landed on Earth. It was amazing! He stepped in, closing the door behind him. He inspected all the equipment in awe, wondering how it had all gotten here. Was _this_ how Dumbledore knew about him?

He sat in the chair in front of the computer. "Computer?" he asked.

A mechanical voice exactly like the one 'back home' responded. "I am at your command."

He grinned, removing his wig and lenses. This was going to be fun. "Look up 'Lord Voldemort'. See if you can get into any 'magical archives'."

"Files are being hidden by the Ministry of Magic."

"What is this 'Ministry'?" Zim hissed. "How dare they keep me out! Computer! Crack those files!"

A few moments later, tons of folders appeared on the large screen, translating from English to Irken text. His eyes widened as he read. One human. _One_ human had done all that damage. He began laughing maniacally, imagining all the things he'd be able to do once he learned the right spells.

He glanced at a conveniently placed clock and saw that it was nearly five. "Crap," he muttered. He left the room and raced back to the Common Room. Luckily for him, sometimes the Fat Lady talked in her sleep, so he was able to give the password without waking her. He plopped down on the couch and decided to get his sleep there.

He was woken up by the sound of footsteps on the stairs. He hastily put on his wig and contacts, setting them into place just in time as the boys came piling down.

"You're up early again," Ron noted. Zim shrugged.

"What are you all doing down here already?" he asked, noticing that it was earlier than yesterday when they came down.

"About that—" Seamus started, glaring at the alien, but was cut off by a loud, insane scream that sounded something like 'BURITOOOOOOOS'.

"Oops…" Zim said. In hindsight though, it had been a good idea not to take GIR on his venture last night. He'd never have made it down the staircase with how loud that robot was.

Everyone else tromped down the stairs, all looking quite annoyed at being woken up so early by a screaming robot. "What the bloody hell was that?" one of the Weasley twins asked.

"Zim's got a talking dog," Harry tattled, and Zim sent him a dirty look. "He's a little… crazy."

"Sorry about that," Zim said. "He, um… drank too much caffeine… when he was born. Yeah." He congratulated himself on a good lie.

"If he does that one more time," Ron warned. "We're going to Dumbledore." Zim knew he was in trouble now.

It was Saturday, so there was really nothing to do. He did, however, become somewhat interested in a game called 'Chess'.

"What does that piece do?" he asked, pointing to the rook.

"It can move forward and backwards, or to the side," Ron responded, never taking his eyes off the game. He was playing against the board itself, which also interested Zim.

"And that one?" he pointed to the king.

"That's the piece you're trying to protect. If your king's captured, the game's over, and you've lost. If you can't move your king in any way that would save it, it's called a Checkmate. You can lose that way, too. If you take your opponent's king, or checkmate him instead, you win," Ron said. He looked at all the pieces on the board and moved a bishop. "Checkmate."

Zim looked from him to the chessboard, temporarily forgetting his contempt for humans. "Can I play?" he asked.

"Sure," Ron said, and turned the board so that it was between them. "You can be white, because white goes first."

"Okay," Zim said, copying the setup of the pieces from Ron's side. He looked from the board to Ron and smirked. "Don't go easy on me, okay?"

Twenty minutes later, Ron stared at the board. He couldn't believe it. Zim, who'd never even _heard_ of chess before today, beat him. Badly.

Zim laughed, and started to stand up, but Ron said, "I demand a rematch."

Zim sat back down, still chuckling a bit, and said. "Fine. I hope you _like_ losing." And yet again, he beat Ron. He smirked triumphantly. "I suppose you want another rematch?"

"Uh, no, I'm good…" Ron said, standing up and putting his board away. Zim watched him leave and sighed. He was so bored. Maybe he could sneak up to that room on the seventh floor again…

They got their grades on their Potions back on Monday. Zim growled as he saw the 'P' on his paper. How could he have been rated 'Poor'? His potion had been _perfect_! And yet most of the Slytherins got at least an 'A', when most of their potions could be considered worse than dirt.

"Fine," he hissed under his breath. "You want to fail me? I'll give you something worth failing." And after that day, he stopped following the instructions, and just threw random things into his cauldron. He never did his essays; instead, he doodled on the paper and handed that in. He enjoyed the outcomes of his potions. One time, an annoying Gryffindor girl, Lavender Brown, got too close. Her nose grew to three times its size.

He walked into Transfiguration one day to see McGonagall glaring at him. "The Headmaster would like to see you in his office," she told him sternly, and he headed back out the door.

Once the halls were clear, he allowed a mini-screen to come out of his PAK. "Give me a map of the school," he told it, and a 3D map appeared in front of him, with a little dot labeled 'You Are Here'. "Show me the way to Dumbledore's office." A line slowly snaked from the dot to a room a few floors up. He followed the direction of the line and found himself in front of a gargoyle. "This can't be right," he muttered.

The gargoyle looked at him. "Are you Zim?" the alien nodded, and the gargoyle stepped out of the way. "He's expecting you."

As Zim climbed the stairs, his only thought was: This was about GIR. This had to be about GIR. The boys had warned him repeatedly that if GIR kept waking them up, they'd report him, and the robot woke them up every morning anyway. He was like Gryffindor's personal alarm clock.

He opened the door, and sure enough, GIR was sitting in one of the chairs, with the 'hood' of his disguise down.

"Ah, there you are," Dumbledore said. "You seem to be having a little bit of a problem regarding GIR."

"Yes, everyone's complaining about how he's always waking them up in the morning."

"Oh, no, I think that's actually a very good thing," Dumbledore said. "In the last few years, too many Gryffindors have overslept and missed classes. This will be a nice change of pace. However, you're here now because of what he does to the dorm while you're in class."

"I know, I'm sorry," Zim replied.

"So," the Headmaster continued. "I decided that it would be better for you to just bring him with you to all of your classes."

"What are you, nuts?!" Zim asked, temporarily forgetting that Dumbledore was currently his figure of authority.

"No. I've already spoken with all the teachers, and with the exception of Professor Snape, all of them have agreed to let him accompany you."

"Why does that not surprise me?" Zim muttered.

"So, while you are in Potions, GIR will come here, and I'll be keeping an eye on him. Do we understand each other?"

Zim saluted the Headmaster. "Yes, sir." He left the office and GIR followed. As soon as the door closed, he stopped. Had he just treated a human like he owed him some sort of loyalty?

He shook himself. No, he was just reminded of how he'd received many orders from the Tallests. It was just a reflex. That's all.

Yet he still couldn't shake the feeling that it might have been something else.


	5. Oops

**Disclaimer: Have you really not figured this out yet?**

Somehow, Zim had gotten into a semblance of friendship with Ron and Harry. He'd hang out with them during some of his free time. He would help them with their homework, but after days of them still not getting it, he just let them copy his homework.

They were still surprised by how smart Zim could be, considering his usually stupid actions. When it came to essays, though, they were very thankful for it.

It was time for flying lessons. Zim had no interest to fly a broom when he could easily just use the Voot Cruiser, his PAK, or GIR. Speaking of whom…

GIR was running around on the field where they were to practice. "GIR!" Zim yelled, and the robot stopped and walked over.

"That's a pretty ugly dog," a Slytherin, Malfoy, said.

"Oh, shut up, Malfoy," Harry told him.

Zim ignored this exchange, excited to see what his handiwork could do. He'd managed to program some simple magic into GIR's system, and became very curious as to whether he'd be able to fly a broom. So when it came time to make the brooms rise, Zim just leaned on his broom and watched GIR.

"Up!" he yelled, and the broom hit the robot straight in the head, making him fall over. Zim smacked his forehead and picked GIR up. Okay, no flying for him. He watched as Neville's broom rose up against the boy's will and sighed. This could only end in disaster.

He'd come to know Neville fairly well, too. And Neville Longbottom was actually a pretty decent student. He was just too afraid of Snape to ever be able to learn anything in Potions. So Zim took to tutoring him as well. He had no idea why he was helping these humans, though. He kept telling himself it was to just pass the time. But he knew Neville had awful luck, and he was right. He winced as Neville was smashed into the wall, and actually almost sent GIR up to retrieve him. But that would blow his cover. So he just watched as Neville plummeted to the ground.

He watched with amusement as Malfoy taunted Harry, and laughed when Harry proved to Malfoy just how great he could fly. He knew the boy was going to get in trouble, though, and his thoughts were confirmed as he watched McGonagall storm out and take Harry inside.

When he found out that Harry had made the Quidditch team, he congratulated him, and then retreated to his lab. He needed some time alone and the lab was the only place he was able to do it.

As he removed his disguise, he frowned. Why had he been so worried about Neville getting hurt? He was just a human. And when Harry had made the team… was that happiness he'd felt? He shook his head. No. No, that couldn't be it. Invaders needed no one! But he continued to contradict himself immensely.

_ZZZZZZZZZZZZZZZZZZZZZZZZZZZZ ZZZZ_

It was Halloween night, and the rest of the school was in the Great Hall for the feast. Zim, however, had skipped dinner and was working in his lab. He was just on his way down when he heard some loud, thudding footsteps. He turned a corner and saw a large creature in the middle of the hall. It held a large club, and wore a very stupid expression on its face. It turned to see Zim and growled.

"Uh oh," Zim said, realizing that he'd been spotted. He bolted into the first open door he found, which turned out to be the girls' bathroom.

"What are you doing in here?!" Hermione, who Zim had watched run off crying earlier, yelled.

"Big creature… out there… saw me… ran in… hiding…" He turned around. "Oh, crap." The creature had followed him.

He was prepared to use Hermione as a meat shield. He was not opposed to that in any way. But there was nothing he could do when it grabbed his ankle and lifted him off the ground.

"Be careful!" Hermione yelled to him. "It's a troll! They're very strong!"

She didn't need to tell him twice. He'd just gotten hit in the head with the club, and were he a regular human, he'd have been knocked out. Luckily, his PAK activated instantly, healing the injury. Unfortunately for him, though, his wig came off. He heard Hermione gasp, but he couldn't worry about that. Survival came first.

Since the wig had already come off, he figured that he might as well remove his lenses too. It was difficult with a troll shaking him, because he had to keep dodging the club. While he was able to stay conscious from a hit from it, it was something he did not want to experience again.

Now that his disguise was off, he was able to concentrate better. His wand had fallen to the floor so that was useless. There was only one thing to do. An arm with a laser came out of his PAK, and shot the troll's hand, making it drop him. He landed with a dull 'thud'. "Ow…" he muttered before standing. He faced the troll angrily. Now it was personal.

GIR, still in his disguise, came running in, then saw the troll. "Oooooohhhh," he said, staring.

"GIR, don't just stand there you idiot, help me!" Zim yelled, still shooting at the troll as it tried to advance on him.

The disguise came off and GIR saluted him, temporarily falling into 'Duty Mode', as Zim called it. "Yes, my Master!" And with that, GIR flew in front of the troll before returning to normal. "What do I do?"

Then Zim remembered that he had neglected to arm GIR with any weapons, because he didn't trust the robot to use them responsibly. "Uh, just… distract it or something while I think of a plan." And while he was thinking, Harry and Ron ran in. The first thing they noticed, obviously, was the troll. The second was a little robot flying around its head. The third was Zim without his disguise.

"What the-?" Ron started, but the troll saw the two boys and began to walk towards them, swatting at GIR like he was an annoying little fly.

"Get out of here, you idiots!" Zim yelled, raising himself on the legs of his PAK. He shot the troll with another laser, drawing its attention again. He wasn't doing this for the humans. No, this was revenge. He wouldn't let the attack against him go unpunished. He just didn't want them to get in the way.

The humans in question, however, had a habit of not listening to orders. Harry threw a loose pipe at the troll, distracting it. That was a bad move, because the next thing Harry knew, he was upside down, in the air, about to be hit by a giant wooden club. He dodged the club every time it came his way. "Do something!" He yelled, and Zim got an idea. He took careful aim and shot a laser right into one of its eyes. With it half blind and in pain, the troll dropped Harry, clutching its wounded, now useless eye. It focused in on his attacker, who smirked. Two long poles shot out the back of Zim's PAK, and a net slid up them. The poles moved forward, shooting the net like a catapult, trapping the troll.

"You can't catch it with just a net!" Hermione said worriedly. "It's going to get free!"

"No it's not," Zim said with a smirk, and a small control was deposited in his hand by another PAK arm. "Just watch." He pressed the button on the control and grinned evilly as electricity ran through the net, shocking the troll until it was unconscious.

Now that they were no longer depending on him to save their lives, the three humans backed away from Zim, looking a bit fearful. It was then that he remembered that he'd removed his disguise in the fight.

He looked over to see GIR, out of his dog suit, splashing in a puddle of water. This would be a bit difficult to explain.

Just then, a group of worried teachers ran in, and stared in shock at the troll, detained by an electrically charged net. Professor McGonagall went to check its pulse. "I wouldn't do that," Zim warned, and the teacher stopped. "That net's charged with 20,000 volts of electricity." McGonagall's hand retreated.

At the lack of surprised stares from the teachers, Zim assumed that they already knew about him, but the three students with him, not so much.

"Professor," Ron started, looking back towards Zim. "What… what is he?"

"Zim is an alien," Snape said simply, and said by anyone else, it would have been funny. "He was sent to our planet to conquer and destroy it."

Harry turned to the alien in question. "Is that true?" he asked, hoping it wasn't. He'd thought Zim was his friend.

But the alien smirked. "Yes, it's true, human earth-monkey." He laughed. "It's all true. My Almighty Tallests sent me here on a secret mission to take over the Earth for the Irken Empire." He let the legs of his PAK carry him to where his wig and lenses lay, not daring to touch the floor, because a few of the pipes had broken in the fight, flooding the bathroom. He put his disguise back on, and GIR jumped into his dog suit. "Now, if you'll excuse me," he said, moving out of the bathroom, letting the legs retreat once he was clear of the water, "I have homework to do."


	6. Not an Invader

**I am SOOOOO sorry, everyone, for the long wait. I have a different account that I promised weekly updates on, so I've been busy with that, and these next few months still aren't going to be easy to update. It's crunch time in school, now, since exams are coming up. After that, I'll be spending the first three weeks of July over in Europe, so I won't have internet, either. I am SO sorry, and I'll try writing more as soon as I can.**

**Disclaimer: Do I really need to say it?**

The fight on Halloween had forged a new friendship, but crushed another. Zim was left alone, and for some reason, that bothered him. He stopped going into the dorm, and just spent his nights on the couch. He knew he wasn't wanted. Harry and Ron had probably told all the other boys about him.

But he didn't give them enough credit. Both boys had kept their mouths shut about Zim. Hermione was doing the same. Not only would people probably not believe them, but they probably owed him their lives. That troll could have easily killed all three of them if Zim wasn't there.

One night, the three sat in the library, chatting quietly.

"What are we supposed to do about Zim?" Hermione asked.

"What do you mean?" Ron asked. "Who says we have to do anything about him?"

Hermione rolled her eyes. "He's going to try to take over the planet. He's an alien, and he's probably going to destroy the world. How can you just sit there and be okay with that?"

"Oh. Good point."

"So what _do_ we do?" Harry asked, but the three were stumped. They knew next to nothing about Zim's race, so they had no idea as to how to stop him.

And unfortunately for them, a few people overheard their conversation. Lavender and Parvati whispered to each other. They just had what was probably the gossip of the century. There was no way they could keep it to themselves.

Zim had been trying to act like nothing happened, other than his sleeping on the couch. GIR was still waking everyone up in the morning, so they were really starting to get angry. That is, until he started making waffles.

"Uh, Zim?" Katie Bell, a second year asked. "How can your dog make waffles?"

"It's kind of a long story," Zim said.

So all the Gryffindors had waffles for breakfast. GIR made good waffles. One morning, though, everyone gave him a wary look.

"What?" he asked, wondering why they were all avoiding him. His eyes landed on Ron, Harry, and Hermione and narrowed. All three shook their head. He turned his head, and saw Lavender and Parvati gossiping with a few of the other girls, and picked out words like 'Zim' and 'alien'. That was all he needed to know. He had to know how they found out. He stalked over to them. "Why are you telling everyone I'm an alien?" he asked, trying to cover up his nerves with anger. "Is it because of my skin condition?"

"We heard Hermione talking about it," Parvati responded quickly, and Zim turned his narrowed eyes to the bookworm. While he wasn't paying attention, Lavender reached over and ripped off his wig, revealing the antennae underneath. The entire House gasped, though Zim had no idea why, because they'd already known anyway. He took out the lenses, glad to not have to wear them anymore.

GIR ran in with a plate of waffles. He set the waffles down and tried to hand Zim his wig back.

"No, GIR," he said. "They know."

So the first thing GIR did was take off his dog suit. With his newfound 'freedom', he started flying around.

Naturally, they got tons of stares. Zim was slightly worried that his mission was compromised, since everyone knew, but if he was right, Harry, Ron, and Hermione would keep his mission a secret. And in a school of magic, an alien wasn't really all _that_ weird, right? He calmed down and went down for classes.

He didn't even bother wearing his disguise, because he knew the truth would be passed through to the other Houses. He let the legs of his PAK carry him down the stairs, because it would be much quicker. A few people screamed, making him laugh in response.

He sat alone in all of his classes, which was just as well. The only slight disappointment was that Neville, whom he had actually started to take a bit of a liking to as an _actual_ friend, was avoiding him too.

That night, he went up to the Seventh Floor again. He'd brought GIR with him this time, because this was probably a good time to add weapons to the robot. It was a good precaution, just in case another troll, or something worse, got into the castle. He had to admit, it had been a pretty close call that night.

Before he got to work on GIR, though, he reasoned that he'd have to report to the Tallests. Surely they were worried about him, because he hadn't transmitted in over two months!

"Zim!" Purple said in surprise when his transmission was answered.

"I am sorry, My Tallests," he said apologetically. "Things on this end have been very busy lately. Actually, right now, I'm a school that is teaching me magic. I know, that sounds pretty unbelievable, but it's true! And there was a wizard named Voldemort, who killed thousand of people. If I can learn this kind of magic—"

"Zim, stop," Red said. "Just stop." He looked at Purple. "I can't take this anymore," he said. "Let's just tell him."

"You weren't sent to Earth on some sort of secret mission," Purple told him. "We wanted to _get rid of you_. We didn't even know there _was_ a planet that far out in space."

"You're defective Zim," Red added. "Very defective. And you are _not_ an Invader. You're just a pain in our sides, so we really don't care what you do anymore. Just don't contact us again." And with that, the transmission was cut off.

Zim stood there, stunned. No, it wasn't true… the Tallests were playing some sort of trick on him… He _was_ an Invader, and a valuable one.

He made his way back to the Common Room in a daze. He lay down on the couch that night, staring at the fire. He'd just lost his purpose in life. He had no reason to be here, or anywhere else. He was very tempted to just self-destruct. But he shook his head. No, he wouldn't do that. He wasn't that weak.

The days dragged on, and all of Zim's grades plummeted. He'd been doing very well in all his classes up to this point, except Potions, which he failed on purpose. People started to notice.

"I think there's something wrong with Zim," Hermione said, sitting down at lunch.

"What do you mean?" Harry asked.

"All his grades have dropped. And have you even looked at him lately? He's like a zombie," she said.

"Uh, no, I didn't," Ron answered. "Sorry that I don't watch him as closely as you do."

"I just wanted to keep an eye on him to make sure he didn't try anything," Hermione hissed. All three shut up when the alien in question walked to the table and sat down next to the brunette. It was the only available seat left.

They were about to get up when he spoke. "No, don't worry," he said dully. "Your planet's no longer in danger. I'm not going to destroy it anymore." The three gave him a puzzled look. On the few occasions that he _had_ spoken about his plans, he became very excited, so what would change all this? "My Tallests told me that I'm defective. I'm no longer an Invader," he said, giving a small, empty chuckle. "I have nothing."

They stared at him for a moment. Was this some sort of trick to lure them into a sense of security? But Zim seemed so sincerely defeated…

Zim grabbed an apple and stood up. "I'll be going now, I guess…" And with that, he moved back up the stairs to the Common Room. When he was sure he was alone, he started pounding the floor. "WHY?!" he yelled. "Why would they do this?!" He pounded his anger out, then stared at the floor where he'd hit. He ignored the stinging pain in his hand and sat up. He curled into a tight ball. He had no idea where GIR was. Maybe the little robot had abandoned him, too. Now he was all alone…

He heard the portrait move and his head shot up. Neville stood in the doorway, looking at him. "Harry told me what happened," he said, and Zim cursed the Boy Who Lived under his breath. Neville sat down next to him. "It's okay, you know," he told the alien. "You've still got friends."

"Oh, you mean the 'friends' that shunned me the moment they found out I wasn't human?" Zim asked. Neville winced.

"I'm sorry," he said. "I was just hurt that you didn't trust me enough to tell me, but you told Harry and the others."

"I didn't _tell_ them," Zim muttered, realizing how it must have looked to Neville. The boy obviously didn't know what had really happened Halloween night. "There was troll in the school on Halloween."

"I know," Neville said. "They herded us back to the dorms."

"Well, I was on my way down when it saw me," Zim started, leaving out the part about the room that acted as his base. That would stay his secret for now. "I ran, and wound up in the girl's bathroom with Hermione. It attacked me and my wig came off, I removed my lenses so I could see a little better. Then Harry and Ron ran in and saw me. I didn't _tell_ them, they saw it."

"Oh…" Neville said. "Well, sorry. Are we still friends?"

Zim chuckled. "Oh, we were never 'friends', Neville. Acquaintances, maybe, but Invaders don't need friends." Neville frowned, clearly put out. Zim grinned. "I guess it's a good thing I'm not an Invader anymore, huh?"

Neville laughed, and for Zim, it seemed a bit better. Yes, he'd lost a big part of his life, but if this was one of the things he got in exchange, maybe it was worth it.


End file.
